This application is in response to program announcement # PA-08-263, in particular the section addressing the clinical quality improvement of continuity of care. Adolescent substance abuse treatment consists of repeated, isolated episodes of acute care. The traditional experimental designs have emphasized the comparison of standardized, fixed interventions as the primary method for evaluating treatment efficacy. Treatment planning based on this approach has overlooked the heterogeneity of both clinical severity and treatment response (Waldron &Turner, 2008). Adaptive Treatment research for adult substance abusers has been developing during the last decade in order to address the heterogeneity in both clinical severity and treatment response (Collins et al., 2004;Sobell &Sobell, 2000). This has been shown to be a promising performance-based procedure in which individuals who respond poorly to an initial level of evidence-based efficacious treatment are then provided a different or a more enhanced version of the same treatment (McKay, 2009). The definitions of non/poor response and the timing of change are pivotal decision rules in an Adaptive Treatment protocol, which includes intervention options algorithm. This approach should be expanded to youth substance abuse treatment outcome research in order to overcome the limitations of traditional interventions and advance the field. Two hundred and thirty consenting and eligible adolescents ages 13 to 18 with cannabis use disorder (CUD) will participate in a randomized controlled study. All participants will receive an effective evidence-based practice intervention that is, 2 individual sessions of Motivational Enhancement Therapy followed by 5 group sessions of Cognitive Behavioral Therapy (i.e., MET/CBT-7) for 7 weeks. Then the poor-responders will be randomized into one of two Adaptive Treatment conditions. The first is an augmented individualized 10 weekly CBT sessions. The second is a different treatment modality, the Adolescent Community Reinforcement Approach (A-CRA). The A-CRA 10 weekly sessions include: 6 individual, 2 parents, and 2 joint. All participants in the study including completers of MET/CBT-7 will participate in follow-up assessments of treatment outcomes at weeks 17, 21, 25, 38 and 52 from treatment onset. The proposed study is viewed as an initial step in the development of comprehensive adaptive treatment strategies for youth with CUD. PUBLIC HEALTH RELEVANCE: The traditional, fixed, episodic treatment for youth substance abusers have overlooked urgent challenges including the: 1) heterogeneity of response, 2) poor response, and 3) difficulty to prevent relapse regardless of treatment modality. The adaptive treatment (AT) approach in this study address the aforementioned deficiencies with an emphasis on meeting the needs of poor responders (PRs) that manifest unfavorable outcomes. The findings generated by this study are expected to support the AT approach and improve treatment efficacy for PRs as well as establish a first step of treatment algorithm of AT for youth with cannabis use disorders.